Introduction

Positron emission tomography (PET) is a noninvasive medical imaging technique that has been rapidly developing in the past several decades. By imaging the uptake and distribution of a radiolabeled molecule, PET is an important diagnostic tool for investigating diverse types of diseases in preclinical and clinical research and drug development. Compared to other imaging techniques, such as magnetic resonance imaging (MRI), computed tomography (CT), X-ray, or ultrasound which provide structural and anatomical information, PET provides quantitative functional information about biological process at the molecular level. Following by in vivo injection of molecules labeled with positron-emitters, PET imaging is accomplished by the detection of two gamma ray photons (511 keV, ~180° apart) from annihilation of a positron (from β+-decay from radiolabeled molecules) and an electron in proximity. Frequently used positron-emitting radionuclides include carbon-11 (11C, half-life...